in ways it does make sense, but chances are most people don't do enough of the other exercises to not work out their biceps - such as chin ups with a hold, pull ups using "hammer" grip, mostly pull exercises utilize bicep muscles - but very few people actually have a pure pull up back routine

plenty of exercises that incorporates biceps which people don't do, so what he says makes sense probably for him if he does those exercises otherwise if your just starting up - you should do biceps anyways and build up the base